1. Field of the Invention
The present invention generally relates to lighted footwear and, more particularly, to a lighting system that flashes a set of light sources after elapse of a random time delay generated in response to closure of a motion-responsive switch.
2. Description of the Related Art
Lighted footwear is popular with men, women and children for reasons of safety by rendering the wearers more visible at night, and for reasons of fashion. Such footwear typically includes at least one light source and preferably a plurality of light sources such as light emitting diodes, a source of power such as a battery, and a switch to connect the battery to the light sources to illuminate them.
The switch can be a simple manual switch as disclosed, for example, in U.S. Pat. No. 4,158,922. The switch could be a mercury switch in which a ball of mercury runs back and forth along a tube between a pair of electrical contacts during motion of the footwear, as disclosed in U.S. Pat. No. 4,848,009. The switch can be a pressure responsive switch which opens and closes in response to application of the wearer's weight on the switch as disclosed, for example, in U.S. Pat. No. 5,285,586. The switch can be a spring switch in which a cantilevered spring in the form of a coil oscillates back and forth to make and break contact with an electrical terminal as, for example, shown in U.S. Pat. No. 5,408,764. The switch may include a metal ball that moves when the footwear moves, as shown in U.S. Pat. No. 2,572,760, or U.S. Pat. No. 5,438,493, or U.S. Pat. No. 5,483,759.
To increase battery life and to provide a more attractive eye-catching and safer display, it is desirable to cause the lights to flash on and off, rather than being maintained continuously illuminated while the switch is closed. This can be accomplished mechanically by the back and forth movement of the above-described mercury or metal balls, or by the oscillation of the aforementioned coil spring, or by the intermittent application of weight in a pressure responsive switch.
Another way to cause flashing is electronically by use of an oscillator or flasher, preferably at low speeds on the order of a few Hertz, as for example described in U.S. Pat. No. 4,158,922. The switch is then used not to make intermittent contact, but instead, a switch closure is employed to trigger an electronic component such as an integrated circuit, such as described in U.S. Pat. No. 5,903,103, to initiate a flashing light sequence.
As advantageous as the known lighted footwear has been, experience has shown that improvements can still be made in their use. Thus, flashing sequences of known footwear are initiated immediately after a switch closure, or after a switch opening. The duration of these sequences is typically fixed. Although visually exciting at first, an immediate, predictable flashing sequence can become boring over time.